One type of system presently used for the direct injection of a fuel into the cylinders of a spark-ignition internal combustion engine incorporates a piston type of pump in which the piston has direct contact with the fuel. One problem in using this type of pump is that the pump is relatively expensive requiring costly noncorrosive materials or coatings in order to combat the corrosive action of active chemicals and water that might be found in the fuel. Moreover, to prevent external fuel leakage, the pump needs special sealing systems for the drive shaft or may need to employ magnetic couplings or bellows type seals in order to prevent leakage. Another problem with the piston pump is that it has a limited life expectancy with the volumetric efficiency of the pump decreasing in time as the clearance between the piston and cylinder increases due to wear. At low speeds such as starting and idle, low volumetric efficiency makes it difficult to prime the system at optimal high pressure. In addition, this type of pump is very sensitive to the impurities that might be found in gasoline and a contaminated fuel could prove to be fatal to the integrity of the pump.